HPUX vfsmount[2]
vfsmount(2) vfsmount(2)
NAME
vfsmount - mount a file system
SYNOPSIS
#include <sys/mount.h>
int vfsmount(
int type,
const char *dir,
int flags,
caddr_t data
);
DESCRIPTION
vfsmount() attaches a file system to a directory. After a successful
return, references to directory dir refer to the root directory of the
newly mounted file system. dir is a pointer to a null-terminated
string containing a path name. dir must exist already, and must be a
directory. dir cannot be a context-dependent file (see cdf(4)). Its
old contents are inaccessible while the file system is mounted.
vfsmount() differs from mount() (see mount(2)) in its ability to mount
file system types other than just the UFS type.
type indicates the type of the file system. It must be one of the
types described below. vfsmount() does not check that the file system
is actually of type type; if type is incorrect, vfsmount() may cause
the process to hang. To prevent such problems, statfsdev() (see
statfsdev(3c)) should be called before vfsmount() to check the file
system type, which statfsdev() places in the f_fsid[1] field of the
statfs structure it returns.
The flags argument determines whether the file system can be written
to (functionally identical to the rwflag argument in mount(2) in this
regard). It also controls whether programs from the mounted file
system are allowed to have set-uid execution. Physically write-
protected and magnetic tape file systems must be mounted read-only.
Failure to do so results in a return of -1 by vfsmount() and a value
of EIO in errno. The following values for the flags argument are
defined in <sys/mount.h>:
M_RDONLY Mount done as read-only.
M_NOSUID Execution of set-uid programs not permitted.
data is a pointer to a structure containing arguments specific to the
value contained in type. The following values for types are defined
in <sys/mount.h>:
MOUNT_UFS Mount a local HFS file system. data points
to a structure of the following format:
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struct ufs_args {
char *fspec;
};
fspec points to the name of the block special file that is to be
mounted. This is identical in use and function to the first argument
for mount(2).
MOUNT_CDFS Mount a local CD-ROM file system. data
points to a structure of the following
format:
struct cdfs_args {
char *fspec;
};
fspec points to the name of the block special
file that is to be mounted.
NETWORKING FEATURES
NFS
An additional value for the type argument is supported.
MOUNT_NFS Mount an NFS file system. data points to a
structure of the following format:
#include <nfs/nfs.h>
#include <netinet/in.h>
struct nfs_args {
struct sockaddr_in *addr;
fhandle_t *fh;
int flags;
int wsize;
int rsize;
int timeo;
int retrans;
char *hostname;
int acregmin;
int acregmax;
int acdirmin;
int acdirmax;
};
Elements in the structure as as follows:
addr Points to a local socket address structure (see
inet(7)), which is used by the system to
communicate with the remote file server.
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fh Points to a structure containing a file handle,
an abstract data type that is used by the remote
file server when serving an NFS request.
flags Bit map that sets options and indicates which of
the following fields contain valid information.
The following values of the bits are defined in
<nfs/nfs.h>:
NFSMNT_SOFT Specify whether the
mount is a soft mount
or a hard mount. If
set, the mount is soft
and will cause requests
to be retried retrans
number of times.
Otherwise, the mount is
hard and requests will
be tried forever.
NFSMNT_WSIZE Set the write size.
NFSMNT_RSIZE Set the read size.
NFSMNT_TIMEO Set the initial timeout
value.
NFSMNT_RETRANS Set the number of
request retries.
NFSMNT_HOSTNAME Set a hostname.
NFSMNT_INT Set the option to have
interruptible I/O to
the mounted file
system.
NFSMNT_NODEVS Set the option to deny
access to local devices
via NFS device files.
By default, access to
local devices via NFS
device files is
allowed.
NFSMNT_IGNORE Mark the file system
type as ignore in
/etc/mnttab.
NFSMNT_NOAC Turn off attribute
caching. By default
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NFS caches attributes
of files and
directories to speed up
operations on NFS files
by not always getting
the attributes from the
server. Names are also
cached to speed up path
name lookup. However
it does allow
modifications to files
on the server to not be
immediately detectable
on the clients.
Setting NFSMNT_NOAC
turns off attribute
caching and name lookup
caching. NFS caches
attributes for a length
of time proportional to
how much time has
elapsed since the last
modification. The time
length is subject to
acregmin, acregmax,
acdirmin, and acdirmax
described below.
NFSMNT_NOCTO Cached attributes are
flushed when a NFS file
is opened unless this
option is specified.
This option is useful
where it is known that
the files will not be
changing as is the case
for a CD-ROM drive.
NFSMNT_ACREGMIN Use the acregmin value.
See acregmin below.
NFSMNT_ACDIRMIN Use the acdirmin value.
See acdirmin below.
NFSMNT_ACREGMAX Use the acregmax value.
See acregmax below.
NFSMNT_ACDIRMAX Use the acdirmax value.
See acdirmax below.
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wsize Can be used to advise the system about the
maximum number of data bytes to use for a single
outgoing protocol (such as UDP) message. This
value must be greater than 0. Default wsize is
8192.
rsize Can be used to advise the system about the
maximum number of data bytes to use for a single
incoming protocol (such as UDP) message. This
value must be greater than 0. Default rsize is
8192.
timeo Can be used to advise the system on the time to
wait between NFS request retries. This is in
units of 0.1 seconds. This value must be
greater than 0. Default timeo is 7.
retrans Can be used to advise the system about the
number of times the system will resend a
request. This value must be 0 or greater.
Default retrans is 4.
hostname A name for the file server that can be used when
any messages are given concerning the server.
The string can be of length from 0 to 32
characters.
acregmin can be used to advise the system the minimum
number of seconds to cache attributes for a
non-directory file. If this number is less than
0, it means to use the system defined maximum of
3600 seconds. The number specified can not be
0. If the number is greater than 3600, 3600
will be used. Default acregmin is 3. is
ignored if NFSMNT_NOAC is specified.
acdirmin can be used to advise the system the minimum
number of seconds to cache attributes for a
directory. If this number is less than 0, it
means to use the system defined maximum of 3600
seconds. The number specified can not be 0. If
the number is greater than 3600, 3600 will be
used. Default acdirmin is 30. acdirmin is
ignored if NFSMNT_NOAC is specified.
acregmax can be used to advise the system the maximum
number of seconds to cache attributes for a
non-directory file. If this number is less than
0, it means to use the system defined maximum of
36000 seconds. The number specified cannot be
0. If the number is greater than 36000, 36000
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is used. Default acregmax is 60. acregmax is
ignored if NFSMNT_NOAC is specified.
acdirmax can be used to advise the system the maximum number
of seconds to cache attributes for a directory. If this
number is less than 0, it means to use the system defined
maximum of 36000 seconds. The number specified cannot be 0.
If the number is greater than 36000, 36000 will be used.
Default acdirmax is 60. acdirmax is ignored if NFSMNT_NOAC
is specified.
RETURN VALUE
Upon successful completion, vfsmount() returns a value of 0.
Otherwise, no file system is mounted, a value of -1 is returned, and
errno is set to indicate the error.
ERRORS
vfsmount() fails when one of the following occurs:
[EBUSY] dir is not a directory, or another process currently
holds a reference to it.
[EBUSY] No space remains in the mount table.
[EBUSY] The super block for the file system had a bad magic
number or an out-of-range block size.
[EBUSY] Not enough memory was available to read the cylinder
group information for the file system.
[EFAULT] data or dir points outside the allocated address space
of the process.
[EINVAL] dir is a context-dependent file (see cdf(4).
[EIO] An I/O error occurred while reading from or writing to
the file system.
[EIO] An attempt was made to mount a physically write
protected or magnetic tape file system as read-write.
[ELOOP] Too many symbolic links were encountered while
translating the path name of file system referred to by
data or dir.
[ENAMETOOLONG] The path name of the file system referred to by data or
dir is longer than PATH_MAX bytes, or the length of a
component of the path name exceeds NAME_MAX bytes while
_POSIX_NO_TRUNC is in effect.
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[ENOENT] The file system referred to by data or dir does not
exist.
[ENOENT] The file system referred to by data does not exist.
[ENOTBLK] The file system referred to by data is not a block
device. This message can occur only during a local
mount.
[ENOTDIR] A component of the path prefix in dir is not a
directory.
[ENOTDIR] A component of the path prefix of the file system
referred to by data or dir is not a directory.
[ENXIO] The major device number of the file system referred to
by data is out of range (indicating that no device
driver exists for the associated hardware).
[EOPNOTSUPP] vfsmount() of a remote device was attempted.
[EPERM] The caller does not have appropriate privileges.
DEPENDENCIES
NFS: vfsmount() fails when one of the following occurs, and returns
the error indicated:
[EFAULT] A pointer in the data structure points outside the
process's allocated address space.
[EINVAL] A value in a field of data is out of proper range.
[EREMOTE] An attempt was made to remotely mount a file
system that was already mounted from another
remote node.
See getfh(2), inet(7), and mountd(1M) for more information.
HP Clustered Environment:
vfsmount() of a local CDFS file system (MOUNT_CDFS) is not
supported from a cluster client. Such a call returns an EINVAL
error.
WARNINGS
Use of mount(1M) is preferred over vfsmount() because mount(1M)
supports all mounting options that are available from vfsmount()
directly, plus mount(1M) also maintains the /etc/mnttab file which
lists what file systems are mounted.
In the HP Clustered environment, the spec and dir arguments should
always be fully expanded pathnames.
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vfsmount(2) vfsmount(2)
AUTHOR
vfsmount() was developed by HP and Sun Microsystems, Inc.
SEE ALSO
mount(2), umount(2), mount(1M).
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